Ace Combat 5: The Unsung War is a 2004 combat flight simulation video game developed and published by Namco for the PlayStation 2. The game was developed by Project Aces, an internal Namco group credited with the development of the Ace Combat series.

Ace Combat 5 features more than fifty licensed real-world jet aircraft. Nonetheless, the game's events and locations are set in a fictional world. The game's main campaign is set during a war between the fictitious nations of Osea and Yuktobania. The storyline revolves around the player character "Blaze", an Osean fighter pilot who leads a four-plane unit known as Wardog Squadron. The Unsung War follows this squadron's exploits as they attempt to ward off the Yuktobanian invasion of their homeland and uncover the truth about the war. Unlike its predecessors, Ace Combat 5 does not include a multiplayer mode as developers did not have enough extended time to implement one.